Unexplained Mild Potassium Deficiency after the flip

I don't ever remember having this for years I have grown larger plants in my slightly undersized GH power Grower RDWC's.Recently IT was clearly aggravated by a Calcium boost in late veg as I seemed to be having a Cal deficiency in veg as my plants got bigger.

However I stopped boosting calcium excessively. I have included pictures. One time it kept going right until harvest. Lately it tends to subside by the third week. I am trying to think of the changes I have made but not that many. One of them is I bought a pair of Advanced Nutrients Connoisseur as a treat around the time I was fed up with watching my PH all day long.

The other is I expanded my Beneficial Microbe selection and sometimes wonder if I have some bennies eating potassium or blocking it somehow? My tenedency is to swap out my 2.5 gallon reservoir every few days but start it a little high around 900. But the plants are drinking around 650 -7 in flowering. Then I top up with what they drink thinking that that extra will make up for them consuming nutrients too quickly.

I am switching to larger reservoirs. Advanced Nutrients was minimally helpful suggesting not to follow PPM using their system? I am starting to wonder if I am just feeding a little hot and having Salt build up as they suck out the nutrients and my PPM goes to <1500. I do not get any typical burn symptoms. I just get this gradual Potasium Deficient symptom breeping up from the bottom oldest sunleaves.

The good news is that most of these leaves need to come off for this strain that needs heavy defoliation! Nevertheless I really need to figure this out? I have a hard time beliving there isn't enough Potassium. I also top up with Jacks so I do not think I can blame AN entirely lol... I am now alternating back with my Collection of GH flora Series to see if indeed it could have something to do with the AN nutrients?

I also thought it could be the lights havbing switched to higher powered LED's but I ran a round with my CMH's and it happened then too. I also wondered if it could be related to the spraying of Banish Geraniol during the first couple weeks of Flowering. My thought was to the extent that K relates to Opening Closing of Stomata that blocked stomata would cause K deficiency but I think it can not work backwards like this?

I also noticed that AN suggests Big Bud supplement during flowering with their line and that might be the amount of extra K they need? But like I said I do not ever remember having this for years growing larger plants in these 2.5 gallon reservoirs so I feel it must be something that I changed that I can not figure out? And specifically it happens as soon as the plants go into flowering.

My next experiment starting today is I have a Tropicanna Cherry going into flowering but this time it will start flowering in the 13 gallon new modified power grower reservoirs I constructed. Maybe the draw down on K is that much that the topped off 2.5 gallon reservoir is not keeping up with it?

Years ago struggled with similar symptoms,I believe my problem was excess Ca blocking other nutrients.

Ive long ago changed my grow style so not up on salt nutrients as others here.

I think you answered your own question-excess calcium is a major culprit for potassium lockout. The majority of "potassium deficiency" symptoms are due to lockout. They are almost always high EC grows too. Once you return your solution to a proper balance, and I recommend lowering the EC a bit as well, then you just have to watch for normal new growth to see if you fixed the problem. Your plants look good too btw, they shouldn't be affected by this.

Another thought I had is I wondered if my Dehumidifer could cause Potassium Symptoms drying out the air too much?

Thank you very much this is what I actually meant to focus on.
Can simply running too high an E.C actually create the condition for Potassium Lockout?
I also read contrary to my simple logic that higher powered LEDs make the plants drink more water which almost suggests that they might prefer lower PPM under higher intesity lights? Of course I was able to still have this condition appear under my previous 2 315's on my Large Plants as well. Instead of making a fresh reservoir with more concentration than they drink, maybe I should give them exactly what I know they are consuming water/nutrient ratio? In my case it seems to be around 6-700 PPM at the .5 conversion...

Rurumo said:

I think you answered your own question-excess calcium is a major culprit for potassium lockout. The majority of "potassium deficiency" symptoms are due to lockout. They are almost always high EC grows too. Once you return your solution to a proper balance, and I recommend lowering the EC a bit as well, then you just have to watch for normal new growth to see if you fixed the problem. Your plants look good too btw, they shouldn't be affected by this.

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Rurumo said:

I think you answered your own question-excess calcium is a major culprit for potassium lockout. The majority of "potassium deficiency" symptoms are due to lockout. They are almost always high EC grows too. Once you return your solution to a proper balance, and I recommend lowering the EC a bit as well, then you just have to watch for normal new growth to see if you fixed the problem. Your plants look good too btw, they shouldn't be affected by this.

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Thank you as well, I hoped this level of mild K deficiency would not overly impact the yield, adn as i mentioned. IT primarily affect leaves that get defoliated with this crazy Strain Golosa by Delicious Seeds. Not to hijack my own thread but this strain finally taught me the significance of Defoliation...

Unexplained?

Cannabis struggles to uptake potassium because it hyperaccumulates calcium carbonate in its tissue. Which neutralizes carboxylic acids in the plant, and creates calcium crystals and soaps, oxidizes aldehydes into phenols aka the dispo flavor.

This is what you smoke if you buy dispo weed where I live:

Hard water + high evaporation + shit genetics + cannabis nutes + cannabis grower = calcium weed, 100% of the time. .

I'd rather smoke a tube of toothpaste than some of this calmag weed people are growing. Almost every single case of tip burn you see in Cannabis gardens is from potassium deficiency. It's not rare or mysterious. Most grows have potassium deficiency starting in veg and ignore it because tip burn is cool.

Look at every single harvest photo on this site: Canoed, burnt, faded, all that crispness is from missing potassium. AKA "light sensitivity".

And if you learnt to grow plants from traditional sources you know potassium is what dictates quality. Pot growers seem to think it's calmag that makes Sour Diesel taste sour?


Tldr the entire country smokes garbage weed because most pot growers skipped the first day of pot growing school: Potassium and sulfur bring the quality, not calnit and magnesium.

plumsmooth said:

Thank you as well, I hoped this level of mild K deficiency would not overly impact the yield, adn as i mentioned. IT primarily affect leaves that get defoliated with this crazy Strain Golosa by Delicious Seeds. Not to hijack my own thread but this strain finally taught me the significance of Defoliation...

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I'm a big fan of delicious seeds, be sure to show us how your plants do when flowering too! I think you'll find your plants do much better at that lower EC. 700 is the upper end, I bet you find great results even at 600 ppm (1.2 EC). At high EC plants might drink less due to "salt stress", and your temps/RH greatly affect a plant's osmotic balance too. Low humidity can make the leaves look gnarly, especially if you have good airflow through the plants-they just start drying out from the edges-but that would be very low humidity. It's nice if you can keep it up around 50% RH through flower, low enough not to encourage botrytis, but high enough for excellent growth and nice looking leaves. Good luck!

WOW that is some INFO!

Crazy because you just addressed a thought (question I was pondering) I had which was could a build up of calcium during veg actually effect the trasition to bloom -- even though there are plenty of available K nutrients after the flip? Meaning the problem actually starts before the flip. Now I am really starting to question the Addition of Advanced Nutrient to my rotation becasue I really don't remember this happening before I started using Anvanced Coniossouer in Veg and into Flowering?

GrodanLightfoot said:

Unexplained?

Cannabis struggles to uptake potassium because it hyperaccumulates calcium carbonate in its tissue. Which neutralizes carboxylic acids in the plant, and creates calcium crystals and soaps, oxidizes aldehydes into phenols aka the dispo flavor.

This is what you smoke if you buy dispo weed where I live:

Hard water + high evaporation + shit genetics + cannabis nutes + cannabis grower = calcium weed, 100% of the time. .

I'd rather smoke a tube of toothpaste than some of this calmag weed people are growing. Almost every single case of tip burn you see in Cannabis gardens is from potassium deficiency. It's not rare or mysterious. Most grows have potassium deficiency starting in veg and ignore it because tip burn is cool.

Look at every single harvest photo on this site: Canoed, burnt, faded, all that crispness is from missing potassium. AKA "light sensitivity".

And if you learnt to grow plants from traditional sources you know potassium is what dictates quality. Pot growers seem to think it's calmag that makes Sour Diesel taste sour?


Tldr the entire country smokes garbage weed because most pot growers skipped the first day of pot growing school: Potassium and sulfur bring the quality, not calnit and magnesium.

Click to expand...

WEll it looks like hte answer was simple: TOO much nutrients! Here is my Tropicana Cherry after 2weeks plus after flip and it looks pretty good certianly none of that creeping up from the bottom tip/edge burn. I really thought it was a deqfiicecny and it may have been lock-out. Maybe excess E.C. simply likes to lock out Potassium K! Now I am worried how much Cal-Mag to add to my recipes considering I am only at 600PPM on the res change but it is creeping up into the 7-8 range it is about time to to a fresh Res after 2 weeks. Res size is 12-13 Gallons of my one big plant which drinks about 1.5 Gallons per day right now... I almost think I could go down to 550PPM -- literally half of what Advanced Nutrients tried to tell me was a fine level to use.